© 2015 Elsevier Inc. This review discusses C. H bond activation of hydrocarbons mediated by rare-earth metal complexes with an emphasis on type of mechanisms. The review is organized as follows: in the first part, C. H bond activations mediated by rare-earth metals and actinides following traditional reaction pathways, such as σ-bond metathesis and 1,2-addition, are summarized; in the second part, nontraditional C. H bond activation examples are discussed in detail in order to understand the underlying mechanisms. The scope of the review is limited to rare-earth metals and actinides, but, in some cases, closely related reactivity of group 4 metals will be included for comparison. The purpose of the review is not only to provide a brief overview of C. H bond activation by f-elements but also to bring to attention unusual C. H bond cleavage reactivity following mechanisms different than σ-bond metathesis and 1,2-addition.